1. Field of the Invention
The present invention relates to a sensor and, particularly, to a temperature sensor preferably used for sensing the temperature of an evaporator.
Moreover, the present invention relates to a sensor adapted to be formed by fixing a cylindrical metal case for accommodating a sensing element on a three-dimensional substrate and, particularly, to a temperature sensor adapted to be formed by installing an installation portion for mounting on an evaporator and a cylindrical metal case for accommodating a temperature sensing element on a three-dimensional substrate in a vertically standing state.
2. Description of the Related Art
In an air-conditioner for a vehicle, a temperature sensor is installed on an evaporator in order to measure the temperature of a refrigerant. The construction of the temperature sensor for an evaporator is explained with reference to FIGS. 12A to 12D. FIG. 12A is a plan view of an evaporator temperature sensing element 110, FIG. 12B is an elevation view from the arrow X12b in FIG. 12A, FIG. 12C is an elevation view from the arrow X12c in FIG. 12A, and FIG. 12D is a sectional view taken along the line X12d-X12d in FIG. 12C.
The evaporator temperature sensor 110 is formed as an insert molding with a resin, wherein an aluminum case 130 for accommodating a temperature sensing element 32 at the top end thereof and an installation portion 126 for mounting on an evaporator are installed on a substantially cubic substrate 120 in a standing state. Grooves 126a for preventing withdrawal are formed on the installation portion 126. A harness 40 connected to a signal wire 42 from the temperature sensing element passes through a vertical wall 120c of the substrate 120. The evaporator temperature sensor 110 is fabricated by accommodating the temperature sensing element 32 in the aluminum case 130, by placing the aluminum case 130 filled with filler 122 in a mold and by insert molding with a resin.
FIG. 13 shows a state in which the evaporator temperature sensor 110 is installed on an evaporator 50.
The evaporator temperature sensor 110 is installed by inserting the aluminum case 130 and the installation portion 126 into spaces between fins 52 of the evaporator 50.
In the patent documents 1 to 4, air-conditioners for a vehicle using an evaporator temperature sensor are disclosed.
[Patent Document 1]                Japanese Unexamined Patent Publication (Kokai) No. 2002-211,233        
[Patent Document 2]                Japanese Unexamined Patent Publication (Kokai) No. 7-237,440        
[Patent Document 3]                Japanese Unexamined Patent Publication (Kokai) No. 6-48,168        
[Patent Document 4]                Japanese Unexamined Patent Publication (Kokai) No. 5-238,253        
In the evaporator temperature sensors 110 of a prior art, however, as the harness 40 is not fixed to the substrate 120, the root portion of the harness 40 at which the harness 40 comes out from the substrate 120 is likely to be bent and is often broken and disconnected due to vibration during operation of a vehicle or the vibration of a compressor of an air-conditioner.
During the insert molding with a resin, however, as heat is exerted at around 250° C., the harness 40 is required to be made of a material having heat resistance higher than or equal to 250° C., and thereby, the cost of the evaporator temperature sensor is increased.
The evaporator temperature sensor may be installed on various positions in accordance with the type of a vehicle or air-conditioner casings. Due to this installation position, the harness is required to be long which makes it difficult to handle. In this configuration, during insert molding, if the harness is long, it is troublesome to set the harness into a mold and easy to insert the harness into the mold. On the other hand, in order to correspond to various installation positions, a plurality of harnesses having various lengths should be prepared, but it is difficult to combine these harnesses having various lengths together by insert molding. Therefore, the manufacturing process is difficult to automatically perform and is, instead, manually performed with resulting increase in the manufacturing cost.
On the other hand, if the harness 40 is not fixed to the substrate 120 by insert molding, the root portion of the harness 40 at which the harness 40 comes out from the substrate 120 is likely to be bent and may be broken and disconnected due to vibration during operation of a vehicle or the vibration of a compressor of an air-conditioner.
In addition, if the relative position of the harness 40 with respect to the evaporator temperature sensor 110 is not fixed, when the evaporator temperature sensor 110 is installed on the air-conditioner case, the bend of the harness 40 must be adjusted. Due to this, there is a problem in which it is difficult to automate the installation of the evaporator temperature sensor 110. The operation of installation is explained with reference to FIG. 13.
After the evaporator temperature sensor 110 is installed on the evaporator 50 accommodated in an air-conditioner case 60, the harness 40 is settled into a groove 64, lids 62A and 62B are closed and, thereby, the installation operation is finished. During the operation, if the position of the harness 40 is not fixed, the efficiency of the operation is lowered. Moreover, if the position of the harness 40 is not fixed, automatic assembling is difficult.